:root {
  color-scheme: light;
  --ink: #181a19;
  --muted: #656b67;
  --faint: #8c928e;
  --line: #dfe3e0;
  --wash: #f4f6f4;
  --paper: #fbfcfb;
  --accent: #176b58;
  --accent-wash: #e7f1ed;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
  --sans: "Avenir Next", Avenir, "Segoe UI", Helvetica, Arial, sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --page: min(1120px, calc(100vw - 48px));
  --reading: 720px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration-color: var(--line); text-underline-offset: 4px; }
a:hover { color: var(--accent); text-decoration-color: currentColor; }
img, svg { display: block; max-width: 100%; }
button, input { font: inherit; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgb(223 227 224 / 0.8);
  background: rgb(251 252 251 / 0.92);
  backdrop-filter: blur(16px);
}
.header-inner {
  width: var(--page);
  min-height: 68px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.wordmark {
  font-family: var(--serif);
  font-size: 23px;
  font-weight: 600;
  text-decoration: none;
  letter-spacing: -0.02em;
}
.wordmark span { color: var(--accent); }
.site-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 14px;
}
.site-nav a { text-decoration: none; color: var(--muted); }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--ink); }
.header-cta {
  padding: 8px 14px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  color: var(--ink) !important;
}
.menu-toggle { display: none; }

.page {
  width: var(--page);
  margin: 0 auto;
}
.hero {
  min-height: 74vh;
  display: grid;
  align-content: center;
  padding: 120px 0 104px;
  border-bottom: 1px solid var(--line);
}
.hero.compact {
  min-height: auto;
  padding: 104px 0 84px;
}
.kicker, .section-label {
  margin: 0 0 20px;
  color: var(--accent);
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 500;
  text-wrap: balance;
}
h1 {
  max-width: 980px;
  margin: 0;
  font-size: clamp(54px, 8.2vw, 108px);
  line-height: 0.98;
  letter-spacing: -0.055em;
}
.compact h1 { max-width: 850px; font-size: clamp(48px, 7vw, 84px); }
.hero-copy {
  max-width: 700px;
  margin: 36px 0 0;
  color: var(--muted);
  font-size: clamp(19px, 2vw, 24px);
  line-height: 1.55;
}
.definition {
  max-width: 880px;
  margin-top: 52px;
  padding-left: 24px;
  border-left: 3px solid var(--accent);
  font-family: var(--serif);
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1.4;
}

.chapter {
  padding: 112px 0;
  border-bottom: 1px solid var(--line);
}
.chapter-grid {
  display: grid;
  grid-template-columns: minmax(180px, 0.7fr) minmax(0, 2fr);
  gap: 80px;
}
.chapter h2 {
  max-width: 760px;
  margin: 0 0 30px;
  font-size: clamp(38px, 5vw, 64px);
  line-height: 1.08;
  letter-spacing: -0.035em;
}
.chapter h3 {
  margin: 48px 0 10px;
  font-size: 28px;
  line-height: 1.25;
}
.prose { max-width: var(--reading); }
.prose > :first-child { margin-top: 0; }
.prose p { margin: 0 0 24px; }
.prose .lead {
  color: var(--ink);
  font-family: var(--serif);
  font-size: 27px;
  line-height: 1.48;
}
.muted { color: var(--muted); }

.curve {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin-top: 56px;
  border-top: 1px solid var(--ink);
}
.curve article {
  min-height: 250px;
  padding: 24px 28px 28px 0;
  border-right: 1px solid var(--line);
}
.curve article + article { padding-left: 28px; }
.curve article:last-child { border-right: 0; }
.curve .index {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 12px;
}
.curve h3 { margin: 52px 0 10px; font-size: 28px; }
.curve p { margin: 0; color: var(--muted); font-size: 15px; }

.comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  margin-top: 56px;
  border: 1px solid var(--line);
}
.comparison article { padding: 36px; }
.comparison article + article { border-left: 1px solid var(--line); background: var(--wash); }
.comparison h3 { margin: 0 0 28px; font-size: 27px; }
.steps { margin: 0; padding: 0; list-style: none; counter-reset: steps; }
.steps li {
  counter-increment: steps;
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 10px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 15px;
}
.steps li::before {
  content: counter(steps, decimal-leading-zero);
  color: var(--faint);
  font-family: var(--mono);
  font-size: 11px;
  padding-top: 4px;
}
.after-state {
  min-height: 242px;
  display: grid;
  place-items: center;
  padding: 48px 24px;
  text-align: center;
  font-family: var(--serif);
  font-size: 30px;
}
.measure {
  margin-top: 32px;
  color: var(--accent);
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.03em;
}

.use-list { margin-top: 36px; }
.use {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 40px;
  padding: 38px 0;
  border-top: 1px solid var(--line);
}
.use:last-child { border-bottom: 1px solid var(--line); }
.use h3 { margin: 0; font-size: 24px; }
.use p { max-width: 640px; margin: 0; color: var(--muted); }

.principle {
  max-width: 900px;
  padding: 64px;
  border: 1px solid var(--line);
  background: var(--wash);
  font-family: var(--serif);
  font-size: clamp(25px, 3.2vw, 38px);
  line-height: 1.42;
}

.artifact {
  margin-top: 48px;
  border-top: 1px solid var(--ink);
}
.artifact-row {
  display: grid;
  grid-template-columns: 120px 1fr 180px;
  gap: 24px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  align-items: baseline;
}
.artifact-row time, .artifact-row span:last-child {
  color: var(--faint);
  font-family: var(--mono);
  font-size: 11px;
}
.artifact-row span:last-child { text-align: right; }

.privacy-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin-top: 48px;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--line);
}
.privacy-strip div { padding: 30px 28px 30px 0; }
.privacy-strip div + div { padding-left: 28px; border-left: 1px solid var(--line); }
.privacy-strip strong { display: block; margin-bottom: 8px; font-size: 15px; }
.privacy-strip span { color: var(--muted); font-size: 14px; }

.cta {
  padding: 112px 0 124px;
  text-align: center;
}
.cta h2 {
  max-width: 780px;
  margin: 0 auto 28px;
  font-size: clamp(42px, 6vw, 72px);
  line-height: 1.05;
  letter-spacing: -0.04em;
}
.cta p { max-width: 600px; margin: 0 auto 34px; color: var(--muted); }
.button-row { display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 20px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
}
.button.primary { background: var(--ink); color: var(--paper); }
.button:hover { border-color: var(--accent); color: var(--accent); }
.button.primary:hover { background: var(--accent); color: white; }
.cta form {
  width: min(100%, 560px);
  margin: 0 auto;
}
.cta form label {
  display: block;
  margin-bottom: 8px;
  font-size: 14px;
  font-weight: 600;
}
.cta form input[type="email"] {
  width: 100%;
  min-height: 52px;
  padding: 0 16px;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink);
  background: var(--paper);
}
.cta form input[type="email"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.cta form .button { cursor: pointer; }
.access-hp {
  position: absolute;
  left: -10000px;
}

.docs-layout {
  display: grid;
  grid-template-columns: 230px minmax(0, var(--reading));
  gap: 80px;
  align-items: start;
  padding: 80px 0 120px;
}
.docs-toc {
  position: sticky;
  top: 104px;
  display: grid;
  gap: 4px;
  font-size: 13px;
}
.docs-toc strong {
  margin-bottom: 12px;
  color: var(--faint);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.docs-toc a { padding: 5px 0; color: var(--muted); text-decoration: none; }
.docs-content section { padding: 0 0 72px; scroll-margin-top: 100px; }
.docs-content section + section { padding-top: 72px; border-top: 1px solid var(--line); }
.docs-content h2 {
  margin: 0 0 28px;
  font-size: 42px;
  line-height: 1.12;
  letter-spacing: -0.03em;
}
.docs-content h3 { margin: 42px 0 12px; font-size: 25px; }
.docs-content p { margin: 0 0 20px; }
.docs-content ul, .docs-content ol { margin: 0 0 24px; padding-left: 24px; }
.docs-content li { margin-bottom: 10px; }
.note {
  margin: 28px 0;
  padding: 20px 22px;
  border-left: 3px solid var(--accent);
  background: var(--accent-wash);
  font-size: 15px;
}
.path {
  font-family: var(--mono);
  font-size: 0.88em;
}
.table-wrap { overflow-x: auto; margin: 30px 0; }
table { width: 100%; min-width: 620px; border-collapse: collapse; font-size: 14px; }
th, td { padding: 15px 12px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--ink); font-weight: 600; }
thead th { color: var(--faint); font-family: var(--mono); font-size: 10px; letter-spacing: 0.06em; text-transform: uppercase; }
td { color: var(--muted); }
code { padding: 2px 5px; background: var(--wash); font-family: var(--mono); font-size: 0.85em; }

.site-footer { border-top: 1px solid var(--line); }
.footer-inner {
  width: var(--page);
  margin: 0 auto;
  padding: 42px 0;
  display: flex;
  justify-content: space-between;
  gap: 32px;
  color: var(--muted);
  font-size: 13px;
}
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; }
.footer-links a { text-decoration: none; }

@media (max-width: 780px) {
  :root { --page: min(100% - 32px, 1120px); }
  body { font-size: 16px; }
  .header-inner { min-height: 60px; }
  .site-nav a:not(.header-cta) { display: none; }
  .hero, .hero.compact { min-height: auto; padding: 88px 0 72px; }
  h1, .compact h1 { font-size: clamp(46px, 15vw, 68px); }
  .chapter { padding: 80px 0; }
  .chapter-grid, .docs-layout { grid-template-columns: 1fr; gap: 32px; }
  .chapter-grid > .section-label { margin-bottom: 0; }
  .curve, .comparison, .privacy-strip { grid-template-columns: 1fr; }
  .curve article, .curve article + article { min-height: auto; padding: 24px 0; border-right: 0; border-bottom: 1px solid var(--line); }
  .curve h3 { margin-top: 26px; }
  .comparison article + article { border-left: 0; border-top: 1px solid var(--line); }
  .use { grid-template-columns: 1fr; gap: 10px; }
  .principle { padding: 36px 28px; }
  .artifact-row { grid-template-columns: 80px 1fr; }
  .artifact-row span:last-child { display: none; }
  .privacy-strip div, .privacy-strip div + div { padding: 24px 0; border-left: 0; border-bottom: 1px solid var(--line); }
  .docs-layout { padding-top: 48px; }
  .docs-toc { position: static; grid-template-columns: 1fr 1fr; padding-bottom: 32px; border-bottom: 1px solid var(--line); }
  .docs-toc strong { grid-column: 1 / -1; }
  .footer-inner { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}